Here's my goal and I thought of trying Nintex first. Maybe you have a simpler solution, jscript or something.
I have a library with multiple images and a webpage that displays one image as the background of a Div (via a CSS file), hard coded with a file name. I'd like that image change once a day. Maybe have a workflow copy a random file from the library to the destination library and overwrite the existing file.
My Div that displays the image is like: